Typically, gas turbine engines are equipped with various mechanically-driven accessories which are connected to a casing referred to an accessory gearbox (AGB).
Some accessories are generating intense heat during their operation and for this reason, they require cooling. Typically, oil in the AGB is used for cooling the accessories, particularly the starter/generator unit. Oil passages are provided inside the starter/generator unit and heat is exchanged between the oil and the internal parts of the starter/generator unit. This arrangement has been used in the past in an extensive number of designs. However, it requires oil connectors between the AGB and the electrical device, and also internal oil passages in the electrical device.